The present invention relates to a method for optimizing the joints between layers along portions of the layers which are flush with the surface of a part obtained by computer-aided modeling or prototyping involving layer decomposition, as well as the elementary layers obtained by the method, and the parts resulting from their assembly.
Rapid prototyping methods are themselves known. For example, European Patent No. 0 585 502-B1 discloses a prototype part which is produced using software for decomposing the part to be produced into elementary layers. The layers are assembled together, and the final assembly is then externally reworked, in particular, to remove any roughnesses or imperfections resulting from assembly.
FIGS. 3 and 4 schematically show an assembly of layers which illustrate the problem encountered. In the illustrated assembly of two layers (1, 2), a portion of the joint (3) becomes externally flush, at (4). It will be understood that the zone (5) of the layer (1) comprises little material at this location, which, by machining and polishing, can result in the removal of material from the zone (5) of the joint (3), as is schematically shown in FIG. 4, at (6). This results in an imperfect part, with an irregular surface, which is unsatisfactory for certain applications.
Such conventional joints also have other disadvantages including poor strength, poor resistance to machining, poor resistance to mechanical stresses during use (in particular, compressive stresses, whether they be of mechanical or fluidic origin), poor resistance to all assembly operations (bonding, welding, cementing), and possible deformations during machining, during handling and during assembly.